The two black circles represents "The selling prices that produces no profit." If the selling is 10, the profit is 0. If the selling price is 60, the profit is 0.
The selling price that provides the maximum profit is represented by the red dot. It is between the selling price of 30 and 40. Its maximum profit is equal to 12,000.
F=ar^t if the half-life is 96 years...
.5=r^96
ln(.5)=96lnr
ln(.5)/96=lnr
r=e^((ln.5)/96)
f=800e^(336(ln.5)/96)
f=70.71
So about 71mg will remain after 336 years.
12 | 3*4=12 therefor any number that is divisible by 3 and 4 is also divisible by 12